Insulation



May 5, 1936.

C. OBERMAIER INSULATION Filed March 23, 1952 2 Sheets-Sheet 1 Inventor. Caf l F Oberma'ner:

His Attorneg.

May 5, 1936. c. F. OBERMAIER INSULATION Fild' March 23, 1952 -2 Sheets-Sheet 2 v "u 62 Inventor:

Carl F? Obermaler,

Hi5 Attorneg.

Patented May 5, 1

- INSULATION Carl F. Obermaier, York, Pa., assignor to General Electric Company, a. corporation of New York Application March 23,

21 Claims.

My invention relates to insulation, and has for its object the provision of an improved method and means for insulating electrical conductors and the like.

More specifically, my invention contemplates the provision of improved method and means for applying .an insulating coating of fibrous material, such as asbestos, to electrical conductors, insulating tapes and sheets, etc.

In accordance with my invention, I coat the conductor or other member to be covered with a suitable adhesive and then apply the insulating fibres to the conductor so as to be secured thereto by the adhesive. I prefer to apply the fibres to the conductor in a fiocculent condition and with the fibres separated and arranged in parallelism with each other and with the conductor. Raw asbestos fibres may be suitably prepared for .application to the conductor by means of a carding machine. Q

When insulating an electrical conductor, I compress the fibres after they have thus been applied, and fold them spirally so that they practically surround all portions of the conductor and are fitted closely to it. These operations may be conveniently eifected by advancing the conductor with the fibres attached through a suitable rotating die arranged to compress the fibres and as it rotates to fold them spirally about the conductor.

After this operation'I subject the fibres to a condensing influence so as to distribute them indiscriminately around and about the conductor, thereby producing a felt-like mass of asbestos tightly packed about all port ions of the conductor. This step, in accordance with my invention, is accomplished by bringing the fibres into contact with a fluid condensing medium. I have found that steam, water vapor or a finely atomized water will suitably felt ormat the asbestos fibres.

' After the fibres have thus been matted or felted,

I brush the fibres so as to provide a hard polished surface and to bring the insulated conductor to the desired gauge.

Preferably, after this polishing step, the insu lated conductor will be heated or baked so as to remove the moisture absorbed by the fibres during the condensing operation.

1-932, Serial No. 600,648

vention, reference should be had to the accompanying drawings in which Fig. 1 illustrates diagrammatically apparatus for insulating electrical conductors arranged in accordance with my invention; Fig. 2 is a plan view of certain elements of the mechanism shown in Fig. 1; Fig. 3 is an enlarged elevation of a portion of the mechanism of Fig. 1; Fig. 4 is an end view of the mechanism shown in Fig. 3; Fig. 5 is a diagrammatic .view illustrating another form of mechanism used to insulate an electrical conductor arranged in accordance with my invention; Fig. 6 is a plan view of certain portions of the mechanism shown in trating a portion of the mechanism of Figs. 5 and 6 as utilized to apply insulating covering to insulating tapes, sheets, and the like.

Referring more specifically to Figs. 1-4, inclusive, I have shown my invention in connection with means for applying asbestos fibres to elec-, trical conductors. As shown, the conductors i llrz and illb are drawn from suitable supply spools Ila and Nb by means of a suitable capstan i2. interposed between the supply spools I la and lib and the capstan i2 are idler pulleys arranged, as will be pointed out in greater detail hereinafter, to cause the conductors passed through the apparatus to take certain predetermined directions.

The asbestos fibres which are to be applied to the conductors passed through the apparatus are treated by means of a suitable carding machine so as to produce a fine fleece of fiocculent material, the fibres being separated, and arranged in substantially parallel relation with respect to each other. Y

This carding device is provided with a carding drum l3, a number of worker'rolls and fancies l4 associated therewith, and with feed rolls IS. The raw asbestos fibres, preferably mounted on a suitable supply spool it, are fed to the carding device by means of the feed rolls l5, and, as is well understood, are worked by the worker rolls and fancies so that they are cleaned and combed and separated and arranged in substantially parallel relationship with each other. The fibres thus treated are picked from "the carding cylinder l3 by means of doifer rings H. The carded asbestos fibres are stripped from the doffer rings by means of suitable vibratorycombs l8, one comb being associated with each of the doffer rings.

Each dofier ring and vibratory comb set- I1, l8 serves to provideasbestosfor one conductor Illa, Illb. While I have shown but two electrical conductors fed through the apparatus, it will be understood that a number of conductors will be insulated at the same time. In the particular apparatus disclosed in Figs. 1 and 2, it is contemplated that eight conductors wfll be simul- 5 taneously fed through the apparatus. Consequently eight doffer rings and combs will'be provided.

- Referring to Figs. 1 and 2, it will be observedthat these ring doifers I I are arranged on two levels'of four each. Counting from left to right in Fig. 2, the uneven numbered rings I, 3, 5 and .I are'arranged on the upper level, whereas the even numbered rings 2, l, 6 and 8' are arranged on the lower level. In other words; succeeding ring dofiers I! are arranged on difierent levels, and the ring dofiers on each level are spaced apart a distance slightly less than the width of thedoifer ring.-' As shown in Fig.2, the dofi'er rings on the lower level are arranged so as to lie vertically beneath the spaces provided between the dofier rings of the upper level. This, in effect, provides a series of doffer rings engaging a continuous length of surface of the carding cylinder l3, each dofi'e'r ring, as has been pointed out, ac-/ commodating one conductor, that is, each dofier ring functioning to take ofithe necessary asbestos from the cylinder l3 to insulate one conductor. Preferably, for medium sized conductors, the dofier rings, I! will be so arranged that they will take substantially a 2". width of asbestos fibres from the carding cylinder l3. By arranging the succeeding doffer rings on different levels, as has just been described, I am enabled to insulate the conductors without any possible interference with each other.

The asbestos fibres which have been carded and stripped from the carding'machine by the doffer rings J1 and combs I8 are ready for application to the conductors Illa, lllb, etc. These fibres are picked up by suitable endless conveyors 20 .and are conveyed in streams from the dofl'er rings to points of application to the conductors. v While I have shown but two conveyors 20,

namely those'for the conductors low and Illb, it

will be understood that a conveyor will be provided for each conductor, i. e., for each ring doifer. g 3

The conductors are advanced in such directions relative to the streams of asbestos carried. by the conveyors 20 that as the conductors ad- ,vance they will be brought into contact with the streams of. asbestos. As shown, the conductor I I 0a is directed from the.su'pply spool I la over an idler pulley 2| and over idler pulleys 22 and 23 and thence over idler pulleys 2|, 25'and 26 to the capstan l2, while the conductor "lb is directed over idler pulleys 28and 30 and thence over the idler pulleys 24, 25 and 26 to the capstan l2. It will be observed that the idler pulleys 2|, 22 and 23 provided forthe conductor Ina and the idler pulleys 28 arid ,30 provided for the conductor lllb are so arranged that-portions 3la and 3| b ofthe conductor lengths are caused to travel horizontally through the mechanism in parallel 75 Each conductor Illa, Iflb when leaving its sup- I relation with'each other." Moreover, as shown In other words, the

ply spool Ila, llb is coated with a suitable adhesive so that when the conductor is advanced to its point of tangency with the endless con-- veyor 20 the adhesive will function to pick up the stream of asbestos fibres which are carriedby '5 able adhesive solution, such as shellack, synthetic l5.

resin varnishes, resin, gum solutions, etc., may beused. 7 The angular relationship existing between the paths through'which the conductors and asbestos fibre-streams are advanced is an important fea- 20 ture of my invention in that the conductor comes in contact with the asbestos streams at but a single point. It is unnecessary for the conductorsto touch the conveyor 20 at any time; it is merelynecessary to bring the conductors sufllciently 25 close to the conveyors to allow the adhesive to be brought into contactwith the stream of asbestos fibres carried by the conveyors. If instead of thus arranging the conductors and conveyors 20, the conductors were advanced along the carrying surfaces of the conveyors parallel with them and supported by them, as in devices heretofore. generally used, it is quite likely that the conveyors 20 would have to be providedwith some suitable armor so as to prevent the conductors from wear- 35 ing grooves into their carrying surfaces. This, of course, would add to the complexity and expense of construction of the conveyors. In my apparatus the conductor wire at no time comes into actual contact with the conveyor and hence any 40 tion, i. e., in the condition they are delivered by the carding machine. W i Ashas been pointed out, the'conductors 1a,.

lllb in passingfrom the supply spools Ila, llb

will be provided with a coating of adhesive and, then will be advanced in such directions that the 55 adhesive will function to pick up t he streams of fibres carried on the conveyor belts 20, whereby as'the conductors advance, thesestreams of fibres will be carried along with them.

. From the conveyor belts'20 the conductors pass through suitable dies 34. These dies serve to com-. press the asbestos fibres and to fold the fibres, which have been applied along one. side of the conductors, spirally around and about the. con-- ductors. As shown, the dies 34 are provided with axially arranged conical apertures through which the conductors are passed, thev apertures taper: ing inwardly in the direction of motion of the conductors' These dies will be rotated sothat the asbestos notonly will be compressed upon the conductors as they pass through the dies, but also will be folded spirally around them. This step brings the insulated; conductor appr'oximately to the gauge required.

Then I subject the fibres, which have thus been compressed and folded, to a condensing medium so as to distribute the fibres indiscriminately -all around and about the conductor, I thereby producing a felt-like coatingof insulating material.

For this purpose I subject the fibres to a fluid condensing medium, such as a spray of water, finely atomized, or water vapor or steam. I have found that by subjecting the asbestos fibres to either of these fluid condensing mediums they will be caused to be distributed indiscriminately about the conductor, Thus, they will be caused to assume afelt-like massof insulating mate- 'rial around and about all portions of the conductor passed through the fluid medium. The spiral or folded positions which have been given the fibres by the rotating dies 34 will have disappeared and the felted fibres will be found to completely envelope the electrical conductors This" fluid condensing medium may be applied in any and to provide a smooth and unbroken exterior surface.

For this purpose I provide rotary mechanical brushes 36. These rotary brushes 36 are shown in detail in Figs. 3 and 4. 'For the purpose of illustration', I have taken the rotary brush 36 used in connection with the conductor Illa, it being understood that all of the brushes are identical. As shown, the polisher comprises a pair of polishing shoes or blocks 31 having opposed polishing surfaces 31a. The shoes 3? are pivotally mounted onstuds 38 provided for them on a suitable rotatably mounted supporting body or collar 3%. The studs 38 also function to support suitable tension springs Ml which are arranged to bias the polishing surfaces 31a toward each other. The body'39 is provided with a bearing seat or journal 4! which will be received in any suitable bearing (not shown), and is further provided with a pulley 42 adapted to receive a belt or other suitable mechanical driving member. It will be observed that the polisher 36 is so arranged that the conductor Illa will pass through it axially between the polishing shoes 37 which by conductors are passed through a suitable heating I or baking vchamber lll, thefunction of which is isher itself is rotated on its axis all portions of the; asbestos will be subjected to the polishing action.

After the fibres have thusbeen polished, the

to evaporate any of the condensing medium which has been absorbed and retained by the fibres.

'After the asbestos covering has thus been'dried it is generally desirable to impregnate thefibres with a suitable electrically insulating varnish,

such as lacquer. tors as they are advanced from the oven 3-3 are directed through a suitable bath M, or theinvsulating varnish by means of the idler pulleys 24 and 25.

For this purpose, the conduc- From the bath 44 the conductors are passed through a second heater 45 which serves to dry the insulating varnish, and from this heater they are passed, over the idler pulley 26 which directs them to the capstan l2. conductors are directed over an idler pulley 43 and then received on suitable spools 41.

It will be understood that the capstan l2 which functions to draw or pull the conductors Illa, lllb, etc., through the apparatus will be rotated at a speed bearing a predetermined ratio with the speed at which the streams of fibres are deliveredby the conveyor belts from the carding machine so that the conductors will be ad- From the capstan the vanced at just the right speed to pick up the/ advancing streams of asbestos and carry them along with it. In other words, the speed imparted to the conductors will bear a definite ratio with the speed of delivery of the carded fibres from the machine.

By thus controlling the speed of the conductors through the apparatus and the speed at which the asbestosfibres are brought from the carding machine and further, by controlling the weight of raw asbestos fed into the carding machine, it is possible to accurately control the thickness of asbestos covering, i. e. pounds per thousand feet of asbestos applied to the conductors.

It will be understood, of course, that the mechanical connections between capstan l2 and the carding machine will provide for an even rate of movement of the conductors through the machine rather than to one side only, as shown in Fig. 1.

For this purpose, I provide the apparatus with a pair of opposed carding machines (see Figs. 5 and 6).. In this apparatus, the conductors 50 to be treated are passed from supply spools 5i vertically upwardly between the carding machines. The conductors are advanced by means of a capstan 52 and then delivered to receiving spools 53.

As before, each conductor in being passed through the mechanism is covered with an ad hesive which preferably will be applied by passing the conductor through a suitable receptacle 5 3 which contains the adhesive and operates to apply it to the surfaces of the conductor as it is passed through.

The carding means of this apparatus comprises opposed machines 55 and 56; each of these machines comprises feeding members 5! which serve to feed the. asbestos from a supply roll '53 and deliver it to the carding means proper. The cardrings by means of suitable vibrating combs 63 and the fibres thus picked of! are laid on endless conveyors 84. The conveyors 84 of the opposed doffer rings are themselves opposed and are arranged substantially horizontally. The aligned conveyors of the two machines are spaced apart some- As the conductors advance upwardly from the adhesive receptacles 54 between the opposed conveying belts 84 the asbestos fibres on these belts are applied to opposite sides of the conductors andcaused to adhere thereto by the adhesive coating.

From the conveying belts 84, each conductor passesthrough. a revolving mechanical die 85 which compresses the fibres and folds them spirally around and about all portions ofthe conductor.

Thence the conductor is passed through a suit-- able condensing medium which, as before, may be steain'or water vapor, or highly sub-divided water v particles, 88 directed against the fibres, as by means of suitable opposed conduits 61. This condensingmedium, as has beenpointed out, causes the fibres to be distributed indiscriminately around andabout the conductor.

' After being subjected 'to the condensing me- .dium the conductor is passedthrough a polishing device 68 similar in construction to the polishing device 38 of Fig. 1 and performing the same functions as does this device; and then the conall) ductor is directed through a heater 10 for the purpose of evaporating moisture which has been absorbed by the fibres during the condensing process.

Thereafter the conductors may, if desired, be

' treated, as were the conductors of Fig. 1, by impregnating them with a suitable 1 insulating varnish, such as lacquer. For this purpose each conductor is passed through a suitable receptacle II which receives the varnish and which serves to apply it to the-conductor as the conductor is passed through the receptacle.

, Thence the conductors are passed through a second heater I2 to completely dry the impregnating compound, and from this heater are passed through the capstan 82 to the receiving spool 53.

My method and apparatus may also be utilized to apply asbestos fibres to tapes or sheets of material, such for example, as sheets of cellulosic material, to make an electrically insulating sheet, such as described andclaimed in my copending application Serial No. 576,433, filed November 20, 1931. As there described, this insulation comprises a combination of a sheet of cellulosic material and asbestos fibres coating the sheet.

Referring to Fig. '1 I have illustrated diagrammatically my apparatus for applying asbestos fibres to a sheet of material 80 of the above-men- 'tioned character. The sheet of material 88 is passed vertically upwardly from a suitable supply spool 8| and as it is advanced has its opposite sides coated with a suitable adhesive. The adhesive may be applied by means of opposed rolls 82 engaging the sheet and having their surfaces coated by dipping in adhesive baths 83.

After the adhesive has thus been applied the sheet is directed between a pair of opposed conveyors 84 which convey streams of carded'asbestos fibres from the dofler rings 85 of suitable carding machines not shown) arranged on opposite sides to evaporate any moisture which is absorbed by of the pathbf travel of the material, as shown in Fig. 5.

In this instance it is only necessary to use one dofier'ring 85 and associated stripper 86, and only one conveyor belt 84. The belts and rings will have a length somewhat greater than is the width of the sheet 80 being treated.

As shown, the sheet 80 is directed substantially tangentially to the curved portions of the opposed conveyor belts 84, and as it is thus directed will pick up the streams of asbestos fibres delivered by these belts and then will advance through the mechanism with the fibres attached to its opposite sides.

These fibres, which are arranged on opposite sides of the sheet in substantially parallel relation with each other and with the direction of travel of the sheet, are distributed indiscriminately over the surface of the sheet by means of a fluid condensing medium. As in the previous cases, this medium may be water vapor or steam, or may be highly atomized water particles. Opposed valved-conduits 81 are provided for directing streams of the condensing fluid over theopposite surfaces of the asbestos covered sheet.

asbestos fibres, isepassed upwardly through opposed pressing rolls 8 8 which not only serve to compress the fibres, but also may be heated so as the fibres during the condensing process.

It is to be' understood that my method and apparatus may be used to apply other materials, such'as cotton, jute, and the like to conductors, tapes, and sheets, etc.

' While I have shown particular embodiments of my invention, it will be understood of course that I do not wish to be limited thereto since many modifications may be made, and I therefore con-.

Then the sheet, together with the distributed template by the appended claims tocover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure Letters Patent of the United States is:

1. The method of applying fibrous material to a liquid which has been transformed substantially to the vaporous condition so as to distribute said fibres indiscriminately over the surface of said conductor.

2. The method of applying a fibrous material to a member which consists in applying an ad hesive to said member, separating the fibres of said material and arranging the fibres thus separated in substantially parallel relation with each other, then applying said fibres to said member so as to be secured thereto by said adhesive, then causing said member-to pass through a rotating conical die so as to fold said fibres spirally about said member and then subjecting said fibres to the influence of a liquid condensing medium which has been transformed substantially to the vaporous condition so asto arrange said fibres indiscriminately on said member.

3. The method of providing a filamentary and like member with a fibrous covering which comprises applying an adhesive to said filamentary member and then applying the fibrous material in fiocculent form to one side of-said member so that said material is caused to adherev to said member by the adhesive which is applied thereto,

then folding said fibres spirally about said mem- 75 her so that theysurround and cover all portions of said member, and then subjecting said fibres thus applied to water finely atomized whereby the fibres are indiscriminately distributed around and about said member in a felt-like mass.

4. The method of insulating an electrical conductor and the like which comprises advancing said conductor and as it advances applying an adhesive thereto, arranging the fibres of a fibrous insulating material in substantially parallel relation with each other and advancing said fibres in a stream in such a direction that said stream of fibres is picked up by the adhesive on said conductor and advanced with it, and then subjecting the fibres carried by said conductor to a vaporous medium so asto distribute said fibres indiscriminately around and about said conductor. V

5. The method of applying asbestos fibres and the like to an electrical conductor and like mem 'bers which comprises advancing said conductor and asit advances applying an adhesive thereto, arranging the asbestos fibres in substantially parallel relation with each other and causing said fibres thus arranged to advance in a stream, directing said stream in such a direction that said fibres are picked up by the adhesive on said conductor and advanced with it, then subjecting said fibres as they advance to a fluid condensing medium which has been transformed substantially to the vaporous condition so as to distribute said fibres indiscriminately around and about said conductor, then applying a pressure to said fibres so as to lay them close against said conductor and thereafter heating said conductor so as to evaporate the condensing medium absorbed by said fibres.

6. The method of applying asbestos fibres and the like to an electrical conductor and like members which comprises advancing said conductor and as it advances applying an adhesive thereto, arranging asbestos fibres in substantially parallel relation with each other and causing said fibres thus arranged to .advance in a stream, directing said stream in such a direction that said fibres are picked up by the adhesive on one side of said conductor and advanced with it, then applying a pressure to said fibres so as to lay them closely against said conductor and so as to cause them to assume a spiral position on said conductor, subjecting said fibres as they advance with said conductor to a vaporous condensing medium so as to distribute said fibres indiscriminately around and about said conductor to form a felted mass, then polishing the surfaces of said insulated conductor and thereafter heating said conductor to evaporate the fluid condensing medium absorbed by said fibres.

'3'. The method of applying fibrous material to a member which consists in coating said member with an adhesive, advancing streams of the fibres of said material in opposite directions to opposite sides of said member and applying said fibres to said opposite sides, folding said fibres about said member and then subjecting said fibres to a fluid vaporous condensing influence so that they are distributed indiscriminately over the surface of said member in a felt-like mass.

8. The method of insulating an electrical conductor which consists in advancing said conductor and as it advances covering it with an adhesive, arranging the raw fibres of an insulating material in parallel relation with each other and causing said fibres thus arranged to advance in a stream, directing said advancing stream, so

that said fibres are picked up by the adhesive on said conductor and said stream is advanced with said conductor, causing said conductor with said fibres attached thereto to passthrough a die to compress said fibres and rotating said die. so as to fold said fibres spirally about and around said conductor as it compresses them, passing water vapor over said conductor as it advances so as to distribute said fibres indiscriminately about said conductor in a. felt-like mass, brushing said fibres so as to lay them smoothly against said conductor and so as to gauge said conductor, heating said fibres so as to evaporate any condensing fluid absorbed by said fibres and then path of fibres at but asingle point where said fibres are brought in contact with said adhesive and picked up thereby and advanced with said filamentary member and then subjecting said fibres to a vaporous condensing medium.

it). Apparatus for applying fibrous material to a member comprising means for applying an adhesive to said member, means for receiving and carding said fibrous material, an endless conveyor for receiving the carded fibres from said carding means and for conveying them in a free stream from said carding means through a curved path of motion and means for advancing member on a path lying in the plane of movement of said endless conveyor and substantially tangent to said curved portion of said path so that said member contacts said stream of fibres only at said curved portion where the carded fibres carried by said conveyor are picked up from said conveyor by the adhesive on said member.

11. Apparatus for applying fibrous material and the like to a continuous filamentary member and the like comprising means for covering said member with an adhesive, means for carding the fibres of said material, a conveyor having substantially parallel advancing and returning portions and a curved portion uniting said parallel portions for receiving the fibres directly from said carding means and for conveying said fibres in a free stream on said advancing portion from said carding means and means for advancing said filamentary member along a path in the plane of the path of said stream of fibres arranged at a substantial angle to said parallel portions and having a. portion contiguous with said curved portion of said conveyor so that said member contacts said stream of fibres at but a single point where the adhesive on said member picks up said stream from said conveyor and advances itwith said member. I 12. Apparatus for insulating an electrical conductor comprising means for receiving fibrous insulating material and separating and straightening the fibres of said material so that they are arranged substantially parallel to each other, an

endless conveyor arranged to receive said fibres directly from said carding means and for adva'ncing.themin a free stream through a curved path, means for advancing said conductor along a path arrangedin the plane of movement of said endless conveyor on an angle to said conveyor substantially tangent to said curved path so that saidconductor contacts sajdiree stream offibres on said conveyor at but a 'singlepoint, means for applying an adhesive to said conductor whereby as said conductor is advanced tangent to said conveyor, the fibres are caused to adhere to. said conductor and thereby removed from said a conveyor, means for compressing and turning said fibres spirally about said conductor and means for distributing them indiscriminately around and about saidconductor 13, Means for applying fibrousmaterial to a filamentary member and the like comprising a conveyor for feeding avfree stream of the fibres of said material along -a curved path of motion and means for feeding said filamentary member along a path'in the plane of motion of said fibres and substantially tangentto said curved' path so that said member contacts said free Zstream of fibres only at said curved portion where the fibres carried by said conveyor are applied to said filamentary member.

l4, Apparatus for insulating an electrical conductor and the like comprising means for applyingfibrous insulating material to said conductor and means for subjecting said fibres thus applied. to a fluid condensing medium substantially in, the vaporous condition so as to distribute said fibres indiscriminately around and. about .said conductor. V

15. Means for applying asbestos fibres and the like to an electrical conductor comprising means for applying said fibres to said conductor in substantially'parallel relation with each other and withvsaid, conductor, a revolving conical die engaging said'conductor to fold said fibres spirally about the same and means for applying a vaporous condensing medlunr to said fibres so as to distribute said fibres indiscriminately around and about said'conductor in a felted mass.

16. An apparatus for insulating an electrical said fibres and arranging them spirally aboutsaid conductor; means for subjecting said fibres to water vapor so that they are distributed indiscriminately about said conductor in a felt-like mass and members arranged to apply a force to said fibres and to smooth and polish them to provide a hard; smooth finish for said insulated conductor. a i \i 17.. Apparatus for covering an electrical eon- (motor with a fibrous 'insulaing material comprising a supply-spool for receivingsaid conductor,; means for advancing said conductor continuously from said supply spool, means for cov-o eringv said conductor as it advances with an adhesive, va cardingmachine arranged to receive, "said fibrous insulating material and :deliver it 3 with the fibres oi the materialarranged in sub-- stantially parallel ..relation with each other, a conveyor for carrying the carded fibres from said machine in a stream and forbringing said stream into contact with said adhesivecovered conducm: whereby the stream oi fibres advanced on 4 said conveyor are picked up by said conductor. and carried with. it as it is advanced, a die through which said conductor is passed arranged to compress said fibres, means for rotating'said die so that said fibres are arranged spirally 5 around and about said conductor, means for-subjecting said fibres to a vaporous or fluid medium so that they are indiscriminately distributed around and about said conductor in felt-like form, brushes for engaging said fibres to compress and polish them, heating means for evaporating the vaporous condensing medium absorbed by said fibres and means for impregnating said [fibres with an electrically insulating compound.

18. Apparatus for covering a member with a 1 fibrous insulating material comprising means for coating said member withan adhesive, means for separating the fibres of said material and arranging them in substantially parallel relation with each other, means for advancing said separated and parallel fibres to said member in streams flowing in ditl'erent directions and for applying the fibres of said streams to different portions of said member and means for subjecting said fibres to a vaporous condensing medium so as to distribute them indiscriminately over the surfaces of said member so as to produce a felt like insulating covering. Y t v '19. Apparatus for covering an electrical conductor and the like with a fibrous insulating material comprising means for advancing said conductor and as it advances covering it with an adhesive, means for advancing streams of the 'fibres of said material toward said conductor from difierent directions so that they are picked up by the adhesive covering said conductor, means for folding said fibres spirally around. and about said conductor as it advances and means for subjecting said fibres to a water vapor medi-, um so that said fibres are arranged indiscrimi- 40 nately around and about said conductor: to pro-: I duce a felt-like insulated covering. u

20. Apparatus for applying fibrous material to conductors and the like, comprising a carding device for separating the fibres of said material including a. carding drum, a. plurality of dofler rings arranged in rows at difierent levels operably associated with said drum to pick the fibres from said drum, the rings at each level' being positioned at spaced, intervals and the spaces between the rings of one level being positioned opposite the rings of another level, means for advancing a plurality of conductors. in paths opposite the dofler rings of each level and means for stripping the fibres from said rings and for applying them to said conductors.

21. Apparatus for applying fibrous material to conductors and the like comprising a pairof.

opposed carding devices, each having a carding drum and a plurality of dofler rings arranged;

in two rows at diflerent levels operablyassociated with its-drum so as to pick the fibres from said drum, the rings at each level of each-carding device being positioned at spaced intervals and opposite the spaces of the other level and oppo-. site the corresponding rings oi the other device,. means for-advancing a plurality of conductors in paths opposite the respective opposed rings of each level, and Opposed conveyors opposite each I pair ctcorresponding rings and on opposite sides, of-the corresponding conductor arranged to carry fibres Iromsaid opposed rings to opposite sides of. said conductor.

' CARL r. o'. 7 

